main() {
  Map person = {
    "name":"张三",
    "age":20,
    "sex":"男"
  };
  print("添加map元素------------------>map.addAll");
  person.addAll({"hun":"未"});
  print(person);
    print("删除map元素------------------>map.remove(key)");
  person.remove("sex");
  print(person);
  print("查找map元素是否存在某个value------------------>map.containsValue(key)");
  print(person.containsValue("张三"));//返回布尔值
  print(person.isEmpty);

  
}